Month-End and Quarter Dates Calculator
Find the first and last day of a date's month, its quarter start and end, the year end and the days left until each.
Things to keep in mind:
- If a month end falls on a weekend or holiday, whether a payment moves depends on the contract and the law; the tool does not shift dates.
- Fiscal years that differ from the calendar year are not modelled.
Calculator
Result
Enter the values and press Calculate to see the result here.
About this tool
For the date you choose, this tool returns the first and last day of the month, the start and end of the calendar quarter, the year end and how many days remain until each. It is a practical reference for invoice and payment terms ("end of month", "end of quarter"), periodic reports, rent and subscription periods. It also shows the weekday of the month end, so you can spot month ends that fall on a weekend.
Formulas
- Month start = (year, month, 1)
- Month end = first day of next month − 1 day
- Quarter = ⌊(month − 1) / 3⌋ + 1; quarter start = (year, 3 × quarter − 2, 1)
- Quarter end = quarter start + 3 months − 1 day
- Days left = target date − chosen date (the chosen day is not counted, the target day is)
Quarters follow the calendar year: Q1 January–March, Q2 April–June, Q3 July–September, Q4 October–December.
Example
For 3 October 2026 the month ends on 31 October 2026 (Saturday, code 6) with 28 days left. The date is in Q4: 1 October – 31 December 2026, 89 days to the quarter and year end. For 10 February 2024 the month end is 29 February 2024 (leap year).
How to use
- Pick the date (today's date for today).
- Click Calculate.
- Read the month, quarter and year-end dates and the days left.
Notes
Timezone-free Gregorian calendar. Days-left counts exclude the chosen day and include the target day; if the date already is the month end the result is 0. Quarters follow the calendar year.
Frequently asked questions
See Days in the month. February has 29 days in leap years and 28 otherwise; April, June, September and November have 30, the others 31.
The chosen day is excluded and the month end is included. For 3 October: 31 − 3 = 28 days. If the chosen date already is the month end, the result is 0.
Q1 January–March, Q2 April–June, Q3 July–September, Q4 October–December. Quarters follow the calendar year; businesses with a different fiscal year need a separate calculation.
Find the month end here first, then add 30 days with the Add or Subtract Days tool. For month-based terms use the Add Months and Years tool.
The output is a code from 1 = Monday to 7 = Sunday. For 31 October 2026 the code is 6, which is Saturday; a 6 or 7 means the month end falls on a weekend.
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